Sewn products and method for preventing seam puckering on sewn products

ABSTRACT

Seam puckering on a sewn product made of cellulosic fibers, synthetic fibers and/or animal fibers can be prevented from occurring by simply applying a (meth)acrylate resin finish and/or a polyester resin finish to the seams on the sewn product, then hot pressing the seam. The addition of an acidic catalyst, a polyether compound, or a combination of a cellulose-reactive resin finish with an acidic catalyst to the (meth)acrylate finish and/or polyester resin finish provides a better seam pucker preventing effect on cellulosic fibers than do existing cellulose-reactive resin finishes.

CROSS-REFERENCE TO RELATED APPLICATION

This non-provisional application claims priority under 35 U.S.C. §119(a)on Patent Application No. 2005-085735 filed in Japan on Mar. 24, 2005,the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for preventing seam puckeringon sewn products. The invention also relates to sewn products obtainedby such a method in which seam puckering is prevented from occurring.

2. Prior Art

The seams on sewn products such as garments are generally sewn with asewing machine. When a garment has been sewn, wavy deformations known asseam puckering sometimes arise at the seams, detracting from theappearance of the garment. When seam puckering occurs during sewing, thepuckered seams can be smoothed and flattened by treatment such aspressing to render the deformations inconspicuous.

However, subsequent laundering of the garment may cause it to revert toits original deformed state, allowing seam puckering to reappear.Sometimes laundering even makes seam puckering worse than immediatelyafter the seams have been sewn. Such seam puckering, particularly seampuckering after laundering, is a major problem affecting the appearanceof garments.

Seam puckering due to laundering arises in the two following types ofsituations.

(1) When the machine sewing thread shrinks due to laundering.

(2) When pressing or ironing intended to make seam puckering aftersewing less conspicuous causes the fabric near the seam to beexcessively stretched, giving the fabric a tendency to shrink and returnto its original stage on being left alone or laundered.

One way to prevent seam puckering on laundering that is employed whenpuckering is caused by situation (1) above is to use a machine sewingthread which undergoes little laundering shrinkage, such as polyesterspun yarn or polyester filament yarn. Yet, although such a method isable to better reduce the occurrence of seam puckering than sewingthread having a large laundering shrinkage such as cotton, it cannoteliminate seam puckering due to shrinkage of the fabric.

A solution that has been proposed when puckering is caused by situation(2) above is to place and bond between the two layers of fabric at theseam a tape-like adhesive web or an interlining coated with an adhesive.In this approach, the tape or interlining stabilizes the fabric so thatit does not shrink, making it possible to prevent seam puckering fromoccurring as a result of laundering. However, the tape or interlining isvery troublesome to apply. Moreover, in places such as armholes wherethe seams are curved, the tape or interlining is difficult to applyneatly along the curves. Hence, the productivity and workability arevery poor.

Another effective method for preventing seam puckering is a so-calledpost-curing process in which the fabric is impregnated with a resinfinish in a finishing step, then is simply dried. After sewing, theentire sewn product is heat treated, causing the resin to react.Unfortunately, in this method, because the resin finish is applied in anunreacted state to the entire fabric, long-term storage of the fabric isimpossible. Moreover, there is also the drawback that if the fabric iscreased during finishing or sewing, the creases tend to remainpermanently.

There is also what is referred to as a pre-cure resin finishing processin which treatment up to heat treatment is initially carried out on thefabric in the finishing step, thereby inducing the resin finish to reactwith cellulose fibers. Although this method resolves the drawbacks ofthe above post-curing process, seam puckering is conspicuous and theresulting fabric has a markedly inferior appearance.

JP-A 2004-60071 and JP-A 2004-100131 disclose, as effective means forpreventing the seam puckering of sewn products containing cellulosicfibers in particular, methods in which a cellulose-reactive resin finishis applied to the seams of the sewn products. Although these methods areeffective on sewn products made of cellulosic fiber-containingstructures, there exists a need for a method which is effective as wellon sewn products composed of structures which contain fibers other thancellulosic fibers, such as synthetic fibers (e.g., polyester, nylon) andanimal fibers (e.g., wool, silk).

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a method which canprevent seam puckering not only in sewn products made of cellulosicfibers, but also in sewn products made of synthetic fibers or animalfibers. Another object of the invention is to provide sewn productsobtained by such a method in which seam puckering is prevented fromoccurring.

We have discovered that when an aqueous solution of a (meth)acrylateresin finish and/or a polyester resin finish, to which solutionpreferably at least one selected from among acidic catalysts, polyethercompounds, cellulose-reactive resin finishes, fluorescent pigments andother pigments has been added, is applied by a suitable means such as aspray, brush or roller to the seams on a sewn product and hot pressingis subsequently carried out by ironing or the like, seam puckering onthe completion of sewing can be eliminated. That is, after sewing, theshape of the fabric at seams thereon which have been smoothed andflattened by pressing or ironing becomes set in the smoothed andflattened state due to adherence of the resin, as a result of which thefabric does not shrink. Seam puckering from laundering can thus beprevented from occurring. In addition, by adding an acidic catalyst or apolyether compound to the aqueous solution of a (meth)acrylate resinand/or a polyester resin, the water resistance (laundering durability)of the adhering resin can be enhanced.

The above method may be carried out on any type of fabric material. Forexample, suitable use can be made of fabrics composed of cellulosicfibers, synthetic fibers, or animal fibers; and various fabrics producedfrom blends of such fibers or woven from combinations or mixtures ofdifferent yarns composed of such fibers. Moreover, by adding an acidiccatalyst or a polyether compound or a combination of acellulose-reactive resin finish with an acidic catalyst to the aqueoussolution of a (meth)acrylate resin and/or a polyester resin, there canbe obtained a finish which has an even better seam pucker preventingeffect on cellulosic fibers than do prior-art cellulose-reactive resinfinishes.

Accordingly, the invention provides a method for preventing seampuckering on a sewn product, which method includes the steps of applyinga (meth)acrylate resin finish and/or a polyester resin finish to a seamon the sewn product, then hot pressing the seam. It is preferable for amixture of the (meth)acrylate resin finish and the polyester resinfinish to be applied to the seam. The resin finish may additionallyinclude at least one substance selected from the group consisting ofacidic catalysts, polyether compounds, cellulose-reactive resinfinishes, fluorescent pigments and other pigments. Hot pressing istypically carried out with a hot pressing machine or by ironing.

The invention also provides a sewn product obtained by the foregoingmethod for preventing seam puckering.

Using the method of the invention, seam puckering can be prevented fromoccurring by simply applying a (meth)acrylate resin finish and/or apolyester resin finish to the seams on a sewn product made of not onlycellulosic fibers, but synthetic fibers and/or animal fibers. Theaddition of an acidic catalyst, a polyether compound, or the combinationof a cellulose-reactive resin with an acidic catalyst to the(meth)acrylate resin finish and/or a polyester resin finish enables abetter seam pucker preventing effect to be achieved on cellulosic fibersthan is possible with prior-art cellulose-reactive resin finishes.

BRIEF DESCRIPTION OF THE DIAGRAMS

FIG. 1 is a diagram showing an upper front body section of fabric ontowhich a pocket has been sewn.

DETAILED DESCRIPTION OF THE INVENTION

The inventive method for preventing seam puckering is carried out byapplying a (meth)acrylate resin finish and/or a polyester resin finishto a seam on a sewn product, then hot pressing the seam.

As used herein, the term “sewn product” refers to products obtained bysewing together multiple pieces of textile fabric, such as woven fabric,knit fabric or nonwoven fabric, that are shaped in accordance with theintended shape of the final product, or to products obtained by thesuccessive application of stitches to a single piece of textile fabric.Illustrative examples of sewn products include dress shirts, knitshirts, jumpers, coats, jackets, skirts, trousers, blouses, sweaters,cardigans, outfits, work clothes, uniforms, school uniforms, officeworkwear and sportswear. Items thereon such as collars, sleeves, cuffs,and pockets are also included.

Illustrative, non-limiting examples of the fibers making up theforegoing textile fabric include not only cellulosic fibers such asnatural cellulose fibers (e.g., cotton, linen), regenerated fibers(e.g., rayon, cuprammonium rayon, polynosic, high-strength regeneratedcellulose fibers (e.g., Tencel)) and partially regenerated fibers (e.g.,acetate), but also synthetic fibers such as polyester, nylon andacrylic, and animal fibers such as wool and silk. A single type of fibermay be used alone or two or more types of fibers may be used together inthe form of, for example, blend spun yarn or mixture or combinationweave fabric. Because the invention is particularly effective oncellulose fibers and polyester, the use of 100% cotton products orpolyester/cotton blends is preferred. In polyester/cotton blends, theproportion of polyester is from 0 to 100%, and preferably from 45 to 65wt %.

“Seam on the sewn product” refers herein to the stitches that aresuccessively applied to one or more piece of textile fabric. Suchstitching has a repeating structure shaped as a straight or curved lineformed by repeated crossing of the sewing thread above and below thetextile fabric. Specifically, “seam on the sewn product” includes seamsfor attaching pieces of textile fabric to each other (e.g., plainstitching, reverse stitching), seams to finish the seam allowance (e.g.,top stitched seam, flat felled seam, catch stitching, buttonholestitching), and ornamental stitching for decorative purposes. The sewingthread used is preferably a machine sewing thread having a smalllaundering shrinkage, such as polyester spun yarn or polyester filamentyarn. However, even if a machine sewing yarn having a large launderingshrinkage such as cotton yarn is used, the occurrence of seam puckeringcan be reduced by the method of the invention.

(Meth)acrylate resins that may be employed in the invention are polymerscontaining an ester group-bearing acrylate or methacrylate. Use may bemade of any (meth)acrylic acid ester-containing polymer, includingpolymers obtained by homopolymerizing an acrylate or methacrylate suchas methyl(meth)acrylate, ethyl (meth)acrylate or butyl(meth)acrylate;and copolymers obtained by copolymerizing a (meth)acrylate with anothermonomer such as acrylonitrile, styrene, vinyl acetate or ethylene.However, a (meth)acrylic acid ester-containing polymer which has a highglass transition point (Tg) (preferably at least 10° C., and morepreferably from 20 to 80° C.) and forms a hard coat is advantageous.Examples of suitable copolymers include (meth)acrylic-styrenecopolymers, (meth)acrylic-acrylonitrile copolymers, (meth)acrylic-vinylacetate copolymers and (meth)acrylic-vinyl acetate-ethylene copolymers.Of these, (meth)acrylic-styrene copolymer resins are especiallypreferred because they have a high glass transition point and do notleave conspicuous resin spots on the fabric.

Polyester resins that may be used in the present invention includepolyethylene terephthalate and polybutylene terephthalate. For the samereasons as those given above, it is preferable that these resins have aglass transition point (Tg) of at least 10° C., and especially from 20to 80° C.

In the practice of the invention, it is advantageous to use the(meth)acrylate resin and the polyester resin in admixture. Because the(meth)acrylate resin has a good adhesion particularly to cellulosicfibers and the polyester resin has a good adhesion particularly tosynthetic fibers such as polyester, nylon and acrylic fibers, throughthe synergistic effects of both, a good seam pucker preventing effectcan be obtained in fabrics produced from blends of these respectivetypes of fibers and in combination or mixed weave fabrics made usingboth types of fibers. The mixing ratio of the (meth)acrylate resin andthe polyester resin in such a case may be suitably selected according tothe mixing proportions of the fibers that make up the fabric.

The (meth)acrylate resin and/or polyester resin is preferably used as aresin finish dissolved or dispersed in a suitable medium such as water,methanol, ethanol or isopropanol. The amount of the resin used,expressed as the solids equivalent, is preferably 5 to 25 wt %, and morepreferably 10 to 20 wt %. Too much resin may give areas of application ahard feel and leave resin spots on the fabric, whereas too little resinmay result in a weak pucker preventing effect.

To accelerate curing of the resin finish and enhance its waterresistance, an acidic catalyst may be added to the resin finish used inthe invention. Illustrative examples of the acidic catalyst includeborofluoride compounds such as zinc borofluoride and magnesiumborofluoride; inorganic acids such as phosphoric acid, hydrochloric acidand boric acid; and organic acids such as citric acid, tartaric acid,malic acid, maleic acid and malonic acid. The amount of catalyst added,based on the (meth)acrylate resin and/or polyester resin (total resinweight), is preferably 2 to 15 wt %, and more preferably 4 to 8 wt %.

To improve the water resistance (laundering durability) of the adheringresin, a polyether compound may be added to the resin finish of theinvention Here, “polyether compound” refers to a polymer, surfactant orthe like having a polyether structure, illustrative examples of whichinclude polyethylene glycol, polypropylene glycol, polyethylene oxideand derivatives thereof. Typical, non-limiting, examples of suchderivatives include polyoxyethylene alkyl ethers, polyoxyethylene fattyacid esters, polyoxyethylene-polyoxypropylene glycols, polyoxypropylenealkyl ethers, and polyoxyethylene-polyoxypropylene alkyl ethers.

The amount of polyether compound used, based on the (meth)acrylate resinand/or polyester resin (total resin weight), is preferably 1 to 35 wt %,and more preferably 15 to 25 wt %. Too much polyether compound mayresult in conspicuous resin spotting, whereas too little may weaken theseam pucker preventing effect. In particular, when used on sewn productsmade of cellulosic fiber-containing textile materials, the concomitantuse of a polyether compound greatly enhances the pucker preventingeffect. A better seam pucker preventing effect can be obtained than whenprior-art cellulose-reactive resin finishes are used.

To increase the seam pucker preventing effect on cellulosic fibers, theresin finish of the invention may have added thereto an acidic catalystor both a cellulose-reactive resin finish and an acidic catalyst. Thecellulose-reactive resin finish is a compound having on the molecule atleast two functional groups of one type selected from among epoxygroups, carboxyl groups and methylol groups. Illustrative examplesinclude polyglycidoxy compounds having at least two epoxy groups,polycarboxylic acid compounds having at least two carboxyl groups, andpolymethylol compounds having at least two methylol groups.

The amount of acidic catalyst used in this case may be set within thesame range as that described above. The amount of the cellulose-reactiveresin finish used, based on the (meth)acrylate resin and/or thepolyester resin (total weight of resin), is preferably from 30 to 150 wt%, and more preferably from 50 to 100 wt %.

To prevent a decrease in whiteness or a change in color at areas ofresin application due to hot pressing treatment following application ofthe resin finish to the seams on a sewn product, a fluorescent pigmentor other type of pigment may be added to the resin finish of theinvention.

Methods for applying the resin finish include application with a brush,roller or syringe, and spraying. Spraying may involve application of theresin finish using a trigger-operated container or an aerosol-typecontainer.

The range over which the resin finish is applied may be suitablyselected according to the circumstances under which seam puckeringappears after sewing. However, when the stitches are situated on astraight line, application along the seam over a range of 2 to 10 mm,and preferably 3 to 7 mm, both to the left and to the right of thestitching (i.e., over a total width of 4 to 20 mm, and preferably 6 to14 mm) is preferred.

The pickup of the resin finish applied is not subject to any particularlimitation, and may be selected as appropriate for the textile materialof which the sewn product is made. However, it is preferable for theamount of resin solids, based on the weight of the fabric material, tobe from 5 to 25 wt %, and especially from 10 to 20 wt %. A pickup thatis too high may harden the hand in areas of the sewn product where thefinish has been applied and result in conspicuous resin spotting,whereas a pickup that is too low may diminish the pucker-preventingeffect.

Following application of the resin finish, drying and heat treatment iscarried out along the seams of the sewn product.

Drying following application of the resin finish may be carried out byambient air drying or hot air drying, although drying and heat treatmentcan be carried out at the same time by pressing or ironing. Theapplication of heat treatment while pressing or ironing so as to smoothand flatten seam puckering that has arisen from sewing serves tostabilize the shape of the fabric in a smoothed and flattened state.

Heat treatment by ironing is also possible, although ironing must becarried out with care. Preferred heat treatment methods include pressingtechniques involving the application of pressure which are capable ofsmoothing out seam puckers that have arisen from sewing.

Heat treatment conditions such as temperature and time may be selectedas appropriate for the resin finish to be used. A temperature within arange of 140 to 170° C., and especially 150 to 160° C., is preferred. Atime of at least 15 seconds, and especially at least 20 seconds, but notmore than 60 seconds, and especially not more than 40 seconds, ispreferred.

Pressing is carried out at an applied pressure of preferably at least1.0 kgf/cm², and especially at least 1.5 kgf/cm². The pressure appliedis not subject to any particular upper limit, with a higher pressuregenerally being preferable. The pressure applied is typically up to 3kgf/cm², and especially up to 4 kgf/cm².

According to the invention, a (meth)acrylate resin and/or polyesterresin finish is applied to the seams on a sewn product, following whichpressing or ironing is carried out on the areas to which the resinfinish has been applied, thereby smoothing and flattening seam puckeringthat has arisen during sewing. At the same time, heat treatment toinduce reaction of the applied resin finish is carried out. By means ofthese simple operations, seam puckering can be effectively prevented.

EXAMPLES

The following Examples of the invention and Comparative Examples areprovided to illustrate the invention, and are not intended to limit thescope thereof.

Example 1

Using a pre-cured, resin-finished plain weave (50^(s) warp yarns atdensity of 148 ends/inch, 80^(s)/2 weft yarns at density of 70picks/inch) fabric made from polyester/cotton=65 wt %/35 wt % blendedstaple yarn, an upper front body section for a dress shirt having apocket sewn thereon was produced by an ordinary shirt sewing operation.

The resin finish was applied with a small commercial brush along theseams of the pocket shown in FIG. 1 over a width of 5 mm to the left and5 mm to the right (for a total width of 1 cm) of the seam. ReferringFIG. 1, which is a diagram showing an upper front body section offabric, pocket 2 is sewn with seam 3 onto the upper front body 1.

The resin finish was prepared by adding water to chemicals having theresin formulation shown in Table 1, and bringing the volume up to 100ml. TABLE 1 Ingredient Amount Unikensol AK317¹⁾ 30 wt % Plascoat RZ570²⁾10 wt % Malonic acid  1 wt %¹⁾An acrylic-styrene copolymeric resin (solids content, 50 wt %; Tg, 30°C.) produced by Union Kagaku Kogyo KK.²⁾A water-soluble polyester resin (solids content, 25 wt %; Tg, 60° C.)produced by Goo Chemical Co., Ltd.

The resin finish was applied onto the fabric, then ambient air dried,following which it was pressed with a flat-plate press (produced by KobePress) at a temperature of 160° C. and a pressure of 2.0 kgf/cm² for 30seconds.

The pressed upper front body section was then laundered, and seampuckering of the pocket before and after laundering was visually gradedon a scale of 1 to 5 (1 being the most heavily puckered, and 5 being thesmoothest), based on three-dimensional replicas of seams at each of thefive levels, in accordance with the method of AATCC 88-B-1984. Theresults are shown in Table 3.

Comparative Example 1

Aside from using the prior-art resin finish for cellulose fibers shownin Table 2, treatment of the fabric and evaluation of the seam puckerpreventing effect were =carried out in the same way as in Example 1. Theresults are shown in Table 3. TABLE 2 Ingredient Amount Riken ResinLNB20¹⁾ 15 wt % Aqueous solution of zinc borofluoride²⁾  2 wt %¹⁾A cellulose-reactive N-methylol resin (solids content, 40 wt %)produced by Miki Riken Kogyo KK.²⁾Concentration, 45 wt %; produced by Morita Chemical Industries Co.,Ltd.

Comparative Example 2

An upper front body section was produced using the same type of fabricas in Example 1, but without applying resin finish to the pocket seams.Pressing was carried out under the same conditions as in Example 1. Theseam pucker preventing effects were rated in the same way as inExample 1. The results are shown in Table 3. TABLE 3 Pucker grade AfterAfter Before laundering laundering Resin Finish laundering once 5 timesExample 1 5.0 4.5 4.3 Comparative Example 1 5.0 3.5 3.0 ComparativeExample 2 4.0 2.5 2.3 (resin finish not applied)Laundering Method: Method 103 (home laundering) in JIS L1096, tumbledrying.

As is apparent from Table 3, the sewn product obtained in Example 1 hada considerably higher pucker grade than the product obtained inComparative Example 1 and the product to which resin finish was notapplied that was obtained in Comparative Example 2. That is, the resultsfor the sewn product obtained in Example 1 were excellent anddemonstrated that this sewn product was resistant to seam puckering.

Example 2

Aside from using a pre-cured, resin-finished 100% cotton plain weave(50^(s) warp yarns at density of 148 ends/inch, 80^(s)/2 weft yarns atdensity of 70 picks/inch) fabric, treatment was administered in the sameway as in Example 1, following which the pucker preventing effects wererated. The results are shown in Table 5.

The resin finish was prepared by adding water to chemicals having theresin formulation shown in Table 4, and bringing the volume up to 100ml. TABLE 4 Ingredient Amount Unikensol AP694¹⁾ 30 wt % PEG 20000²⁾  3wt %¹⁾An acrylate copolymer (solids content, 45 wt %; Tg, 24° C.) producedby Union Kagaku Kogyo KK.²⁾A polyethylene glycol (average molecular weight, 20,000) produced bySanyo Chemical Industries, Ltd.

Comparative Example 3

Aside from using the same type of fabric as that described in Example 2and using the same prior-art resin finish for cellulose fibers (shown inTable 2) as that used in Comparative Example 1, treatment of the fabricand evaluation of the seam pucker preventing effect were carried out inthe same way as in Example 1. The results are shown in Table 5.

Comparative Example 4

An upper front body was produced using the same type of fabric as inExample 2, but without applying resin finish to the pocket seams.Pressing was carried out under the same conditions as in Example 2. Theseam pucker preventing effects were rated in the same way as inExample 1. The results are shown in Table 5. TABLE 5 Pucker grade AfterAfter Before laundering laundering Resin Finish laundering once 5 timesExample 2 5.0 4.5 4.3 Comparative Example 3 5.0 4.3 3.8 ComparativeExample 4 4.0 2.5 2.5 (resin finish not applied)Laundering Method: Method 103 (home laundering) in JIS L1096, tumbledrying.

As is apparent from Table 5, the sewn product obtained in Example 2 hada higher pucker grade than that obtained in Comparative Example 3, andhad a much higher pucker grade than the product to which resin finishwas not applied that was obtained in Comparative Example 4. That is, theresults for the product obtained in Example 2 were excellent anddemonstrated that this sewn product was resistant to seam puckering.

Japanese Patent Application No. 2005-085735 is incorporated herein byreference.

Although some preferred embodiments have been described, manymodifications and variations may be made thereto in light of the aboveteachings. It is therefore to be understood that the invention may bepracticed otherwise than as specifically described without departingfrom the scope of the appended claims.

1. A method for preventing seam puckering on a sewn product, comprisingthe steps of: applying a (meth)acrylate resin finish or a polyesterresin finish or both to a seam on the sewn product, then hot pressingthe seam.
 2. The method of claim 1, wherein a mixture of the(meth)acrylate resin finish and the polyester resin finish is applied.3. The method of claim 1, wherein the resin finish additionally includesat least one substance selected from the group consisting of acidiccatalysts, polyether compounds, cellulose-reactive resin finishes,fluorescent pigments and other pigments.
 4. The method of claim 1,wherein hot pressing is carried out with a hot pressing machine or byironing.
 5. A sewn product obtained by the method of claim 1.